The abuse scandal erupted in 2004 when shocking photos emerged of US soldiers appearing to sexually humiliate and torture detainees in Iraq's Abu Ghraib.

None of the photos released on Friday involved detainees held in Abu Ghraib or at the US detention facility at Guantanamo Bay, Cuba, the Pentagon said.

A Pentagon spokesman said the photos had "come from independent criminal investigations into allegations of misconduct by US personnel".

About 14 of the allegations were substantiated - leading to the disciplining of 65 service personnel, ranging from letters of reprimand to life imprisonment. About 42 allegations were unsubstantiated, the spokesman said.

The ACLU has been fighting for more than a decade for the release of what it says are 2,000 photos documenting abuse at US detention centres. It said it would continue to fight for publication of the remaining 1,800.

"The still-secret pictures are the best evidence of the serious abuses that took place in military detention centers," ACLU deputy legal director Jameel Jaffer said in a statement.

"The government's selective disclosure risks misleading the public about the true extent of the abuse."

The Obama administration had agreed to release the photos back in 2009, but then changed its mind saying to do so "was of no benefit" and could inflame opinion against the US.